Land planing machine



Sept. 14, 1954 R. c. HIGLEY LAND PLANING MACHINE 2 Sheets-Sheet 1 Filed Jan. 20. 1947 0. H/GLEY Sept. 14, 1954 R. C. HIGLEY LAND PLANING MACHINE Filed Jan. 20, 1947 2 Sheets-Sheet 2 gwowwtov Patented Sept. 14, 1954 UNITED STATES PATENT OFFICE LAND PLANING MACHINE Rolland C. Higley, Tucumcari, N. Mex.

Application January 20, 1947, Serial No. 722,999

11 Claims. 1

This invention relates to land; planes for use in planing and conditioning the surface of farm lands. a

An important object of the invention is to provide a novel land surfacing apparatus which s highly emcient in smoothing off irregularities in the surface of the ground, and particularly farm lands, to facilitate farming, minimizing erosion, etc.

A further object is to provide a land plane of of novel type wherein the surface of the-ground may be scarified, planed and furrowed with a single apparatus performing a single operation.

A further object is to provide such an apparatus which is supported for movement over the ground in a novel manner so as to minimize irregularities in the'operati'on of the planing element incident tothe passing of thewheel's of the apparatus forwardly of theplam'ng element over uneven ground.

A further object is to provide an apparatus of the characterreferred to" wherein a single novel" control mechanism is employed forlowering the apparatus into operative positionand for raising it to inoperative position with the land planing element out of contact with the ground.

A further object is to provide an apparatus particularly adapted for planing'the surfac of the ground and"wherein-'scarifying and furrow-' ing means may be used in conjunction therewith simultaneously with the land planing element, and wherein the single control mechanism ref'crred to'fun'ctions' automatically when lifting the land planing" element out of contact with the ground to move the other tools; such as thescari fier and furrower, to inoperative positions.

A further object is to provide a novel land planing apparatus which functions more efficiently than presentmechanismsof. this type and wherein amore complete'leveling action may be obtained over relatively uneven groundsurfaces.

A further object is to'provide a novel threepoint' supporting arrangement for the leveler which substantially eliminates lateral tilting of the leveling element incident'to the'passing' of the front supporting wheel over uneven ground.

Other objects and advantagesof the invention will become apparent during the course of the following description;

Inithe'drawings I have shown one embodiment of the invention. In this showing Figure 1 is a side elevation-ofthe apparatus,

Figure'Z is a plan viewof the same, parts being broken away,

Figure 3' is a front elevation of the apparatus,

longitudinal frame members [I are connected by transverse braces 15, It and [1, these braces also preferably being tubular and welded at their ends to the side members I I.

At each side of the apparatus; truss frames 19 are arranged, and each of these frames com'-' prises frame members 20 welded at their remote ends to the frame members H and being inclined upwardly toward their adjacent ends. The latter ends of the truss frame members 20 are welded to each other and tea vertical brace 2! arranged at each side of the apparatus. The truss frame further comprises intermediate vertical braces 22, and any additional bracing which appears advisable, such as diagonal braces 23' and 2d, a supplemental vertical brace25 and a supplemental angle brace '26.

Adjacent the rear end of each longitudinal frame member H is arranged a vertical post 28,

and the upper ends of these'posts are connected by a transverse brace 29. Each post 28 is braced with respect to the adjacent truss member 20 as at- 36. A supporting block 32 is secured to each post 23 by U-bolts 33, and each block 32 carries an axle 34' rotatably supporting a wheel 35. l hese wheels are widely spaced as indicated in Figures 2 and 3, and preferably ar arranged-adjacent the side frame members I l.

The forward cross member [2 is provided with forwardly and upwardly extending ears 38 and to the central cars is pivotally connected as at 39 a normally upwardly and forwardly extending supporting member 40 preferably of I-beam section. This beam is provided with rearwardly diverging brace members 41 Welded at their forward ends to the web of the member 40 and pivotally connected at their rear ends as at 42. The supporting structure comprising the elements 40 and ll accordingly support the forward end of the frame ill, and the parts ar normally arranged in the relative positions shown in Figure This frame comprises lower 1 during the operation of the apparatus, as will become apparent.

The forward end of the supporting member 40 is provided with heavy side plates 45 welded thereto and extending on opposite sides of and welded to a heavy supporting post 46, also preferably formed of I-beam section. The lower end of the post 46 (Figure is provided with a foot 41 preferably welded thereto and provided with depending ears 48 apertured as at 49 to receive a relatively heavy pivot pin 50. The ears 48 straddle a universal block 52 apertured transversely of the apparatus as at 53 to receive the pivot pins 50 and having its lower side arcuately curved, as at 54.

The load on the post 46 is supported by a heavy king pin 55 having a heavy disc 56 at its upper end provided with ears 5! having apertures 58 adapted to receive a heavy pivot pin 59. This pin is also received in an aperture 60 in the universal block 52, the lower curved side 54 of the block 52 permitting lateral swinging movement of the disc 56 therearound,

The king pin 55 is mounted in an axle structure 62 carrying wheels 63 at its opposite ends. The axle 62 carries a forwardly extending draft tongue 64 adapted for connection by a bolt 65 with a tractor or other draft apparatus for pulling the mechanism over the ground.

The apexes of the truss members 20 are connected by a transverse brace I0 (Figures 2 and 3) and a forwardly and upwardly extending relatively long arm 'II is welded at its rear end to the brace I0 substantially centrally thereof. This arm has its forward portion rigidly fixed with respect to the frame I0 by a pair of inverted V-shaped supports I2 and 13, the former of which is welded at its lower ends to the cross member I2 and the latter of which is welded at its ends to the cross brace I5. The forward end of the member II is slotted to receive a heavy plate I4 welded to the member II.

A boom I6 is carried by the load supporting member 40. This boom comprises an arm 11 welded at its forward end to the member 40 and a brace 18 welded to the member 40 adjacent the lower end thereof. The free ends of the members 11 and I8 are secured to each other, and link means I9 is pivoted as at 80 to the joined ends of the members 11 and 18. A pair of pulley blocks 8| and 82 are connected respectively to the link means I9 and plate I4 as at 83 and 84.

A cable 85 is received around the pulleys of the blocks BI and 82, and one end of this cable may be fixed to the arm 11 by means of a lug 86 carried thereby. This lug is also connected to the lower end of a chain 81, the upper end of which passes through a key hole slot 88 in the plate 1-4. This slot is of the conventional type for engaging chains and need not be referred to or illustrated in detail. It will be apparent that the chain 81 limits downward movement of the member 16 relative to the plate 14, and this downward limit of movement may be adjusted by hooking selected links of the chain 81 in the key hole slot 88.

The post 46 is provided at its upper end with a head 90 projecting forwardly thereof and provided with depending ears 9| to which a pulley block 92 is pivoted as at 93. The other end of the cable 85 passes around the pulley of the block 92, thence downwardly around a pulley 94 carried by the post 46 near its lower end, and then extends forwardly for connection with a suitable winch (not shown) carried by the tractor to which the apparatus is connected.

A land planing element indicated as a whole by the numeral I00 is carried by the apparatus intermediate the ends thereof. The element I00 comprises side walls IOI lying adjacent the side frame members I0 and connected at their rear edges by a rear arcuate wall I02 the lower edge I03 of which (Figure 3) extends below the bottom of the side walls IOI. It will be noted that the element I00 has no bottom wall and operates forwardly over the ground to scrape dirt from the high places and pocket it between the side walls IOI forwardly of the wall I02 so that the dirt thus pocketed is free for deposit in any low points over which the apparatus moves. The side walls IOI are rigidly fixed to the frame of the apparatus by U-bolts I04 extending around the vertical braces 2| and 25 and having nuts I05 threaded on their inner ends.

The apparatus may be used solely with the land planing element I00. However, it is preferably employed in conjunction with a scarifier arranged forwardly of the element I00, and may be used with a furrower following the element I00. The scarifier and furrower are indicated as a whole respectively by the numerals I08 and I09, and since they may be identical in construction, only one need be referred to in detail. Each of these units, as shown in Figures 1 and 2, comprises preferably a pair of transverse bars IIO each of which is provided with downwardly extending curved cutter teeth II I, the teeth of the two bars IIO preferably being staggered relative to each other. The bars IIO are carried by side members I I2 which may be braced relative to the bars I I0 as at I I3. The forward ends of the side members II2 are pivoted as at 4 to plates II5 carried by the side frame members I0. Each of the side members I I2 is engageable with an angle bracket II6 adjustably fixed with respect to the adjacent vertical braces 22 by U-bolts II 1.

Means is provided for swinging the scarifying and furrowing units upwardly when the forward end of the apparatus is elevated. One of the cross members IIO of each of these units is connected to the rear end of a cable H8, and the cable associated with the furrowing unit passes upwardly and forwardly and thence around a pulley II9 carried by a central upstanding post I20 secured at its lower end to the cross brace I0. The forward ends of the cables I!!! of both of the units I08 and I09 have fixed connection relative to the post 46, for example by being connected as at I22 to one of the plates 45.

Operation The apparatus normally operates with the parts substantially in the position shown in Figure 1. The scarifier I 08 functions to cut through the surface of the ground and thus loosens the soil to facilitate the planing action of the cutting edge I03. The soil cut by such edge gathers within the side walls I M and rear wall I02 and since the planing element I00 is bottomless, the rear wall I02 merely pushes the dirt over the ground in contact therewith as the apparatus moves forwardly.

The cutting edge I03 is vertically adjusted by clamping the bolts I 04 in the desired position. The relatively raised places on the surface of the ground will be planed oil and as the dirt accumulates within the planing device I00, it tends to slide downwardly and forwardly from the upper end of the wall I02. The capacity of the device lflll is substantialand after a comparatively short; operation of the deviceanadequate quantity ofv dirt will be retained therein to'fill inxany 10w spots over which the apparatus moves; It will be apparent that'as such spots are reached, the dirt within'thedevice I08 merely settles down into the low spots and is sliced off by the cutting edge H33 at the same level as the ground previously passed over. Thus the apparatus operates to cut off the surface of the ground wherever there are rises therein and to deposit the dirt in the low areas to thus effectively level off the ground to prepare it for forming, to prevent or minimize erosion, etc. The action of the device is particularly effective overrelatively flat land as will be apparent.

To better prepare the soil for farming, the furrower I09 is preferably employed, thus minimizing the amount of labor which must be expended later in preparing the ground for planting. While the apparatus is primarily a ground planer, it will be apparent, therefore, that it may be used; in conjunction withother land working tools. Regardless of the use of the furrower, it is preferred that the scarifier be employed to break up the surface of the ground'and thus permit the planing device its to operate with a minimum expenditure of power.

It will be noted that thewheels 35 at the rear of the apparatus are relatively widely spaced but lie within the transverse limits of the planing device Hill. The wheels 35, following behind the planing device, accordingly operate over relatively level ground and stabilize the planing device as to its lateral position, maintaining it quite accurately in horizontal position to prevent one or the other of the ends of the planing-device from digging too deep into the ground.

The wheels 63 at the forward end of the apparatus are relatively closely positioned, as shown in Figure 2, and thus the wheels 35 do not track behind the wheels 63. Attention is invitedto the universal supporting of the lower end of the post 46 relative to the axle 62. This provides the highly advantageous result of permitting the widely spaced rear wheels 3'5 tohold the planing device Hill level regardless of the angularity of the axle 62.

In this connection, it is pointed out that the rear wheels 35 travel over planed ground while over ridges, hollows, etc, in the surfaces of the ground. Assuming that one wheel 63 drops into a ridge, furrow or the like, the axle 52 will immediately assume an angular position which may be substantial. The universal connection of the post 46 with the axle 62, as shown in Figure 5, however, permits the post 46 to remain in a vertical plane without transmitting any twisting forces to the frame it and. associated parts. Accordingly the cutting edge I03 of the planing device remains almost exactly horizontal at all times.

Inasmuch as the planing edge M33 is arranged much closer to the rear wheels 35. than to the front wheels 63, variations in the vertical positions of the wheels 53' are reflected in a much shorter vertical movement of the cutting edge Hi3. For example, assuming that one of the wheels 63 should drop into a hole IOinches deep, the center of the axle 62 will drop downwardly inches. With the proportioning of the parts as shown, and as used in actual; practice, this will result in a verticalv movement of the cutting edge 13 by only about 2 inches. However, it is also pointed out that theframeof the apparatus lies relatively close to the ground and a substantial drop in the position of the universal connection in Figure 5 incident to the dropping of one of the front wheels into a hole or ridge will result in the contactingof the forward end of the frame it with the ground 2ll' to limit downward movement of the cutting edge I03. Under such conditions, the frame It acts as a skid and in the preferred operation of the apparatus any downward movement of the cutting edge I113 is limited to about 1 inch. Under all conditions, therefore, theap-paratus operates with remarkable accuracy in smoothly planing the ground.

The adjustment of the parts, of course, will depend largely upon the nature of the ground being leveled; The planing device Hill is vertically adjustable by means of the U-bolts Hi l, as stated. The scarifier and furrower also are vertically adjustable by loosening the U-bolts ill andraising and lowering the angle brackets H6 (Figure 4).

In moving the apparatus to and from a field of operation, the front end of the frame It and associated elements are elevated. A suitable Windlass (not shown) on the tractor is operated to wind. the forward end of the cable 85'. This operation pulls forwardly on the cable and exerts a forward and upward pull on the sheave block 8 I. This action elevates the rear end of the structure comprising the posts 48, supporting member t'll, braces 4| and arms ii and 18. Since the entire load of the forward end of the frame H) is supported by the pivot pins 39 and 42 (Figures 1' and 2) it will be apparent that this entire rigid structurewill be swung forwardly about the axis of the pivot pin 55 (Figure 5) the post itmoving substantially to a vertical position and'elevating the forward endof the frame Ill and associated elements a substantial distance.

With the post it swung to a substantially vertical position, the elevation of the forward end of the frame m will be more than suiiicient to move: the cutting edge I513 to a position several inches above the surface of the ground. At the sameitime that this operation takes place, it will be noted that the swinging of the post forwardly exerts a pull on the cables I l8, andv accordinglythe scarifier and furrower will beswung upwardly about their pivots H 4 to beheld by the cables I It wholly above the surface of the ground. The apparatus can thenv be transported by the tractor to and from its site of operation without contact of the workingtools with the ground.

From the foregoing it will be apparent thatthe present apparatus is highly suited for efficient use in leveling-uneven ground, the planing device Elli), with the parts properly adjusted, accumulating dirt therein and pocketing a substantial amount of' dirt'ready for use in filling in any low spots encountered over the surface of the ground. The higher areas are planed off by the cutting edge N33. The wide spacing of the wheels 35 without extending them beyond the transverse limits of the planing device provides anarrangemerit whereby the cutting or planing device remains in horizontal position. The wheels 35 always run over planed ground and thus remain substantially at the same level. Any swinging movement of the axle 63 is prevented from being transmitted to the earth working tools by means of the universal connection shown in Figure 5.

It also will be apparent that the present apparatus provides novel means operable through the single control cable 85 for rendering the apparatus operative or inoperative regardless of the number of tools carried by the frame I0. The raising of the forward end of the frame directly lifts the cutting edge I03 out of contact with the ground, while the forward swinging of the post 46 simultaneously and automatically swings upwardly to inoperative position any working tools other than the planing device I which are carried by the frame. The apparatus has been found so efiicient in operation that it not only performs its work with a high degree of accuracy but permits a much greater area of ground to be planed in a given length of time than can be done with mechanisms of a similar character.

I claim:

1. A land planing apparatus comprising a frame having forward and rear ends and including a cross bar at the forward end adapted to be posi-,'

tioned in relatively close proximity to the ground, relatively widely spaced supporting wheels at the rear end of said frame, relatively narrowly spaced supporting wheels at the front end of said frame, universal supporting means for the forward end of said frame connected to said supporting wheels at the front end of the frame centrally of the width thereof and normally supporting said cross bar out of contact with the ground, said wheels and said universal supporting means supporting said frame for movement over the ground with said forward cross bar in relatively close proximity to the ground, said forward cross bar moving upwardly and downwardly incident to variations in the vertical position of said supporting wheels at the front end of the frame and said universal supporting means with respect to the ground, whereby when the universal supporting means and the supporting wheels at the front end of the frame drop a predetermined amount with respect to the ground said forward cross bar will engage the ground to limit further downward movement of the forward end of said frame, and a land planing device carried by said frame and comprising a rear wall having a lower horizontal cutting edge and side walls, the bottom of said 'device being open for the direct movement over the ground of earth out by said cutting edge and pocketed within said device.

2. A land planing apparatus comprising a frame having forward and rear ends and including a cross bar at the forward end adapted to be positioned in relatively close proximity to the ground, relatively widely spaced supporting wheels at the rear end of said frame, relatively narrowly spaced supporting wheels at the front end of said frame, universal supporting means for the forward end of said frame connected to said supporting wheels at the front end of the frame centrally of the width thereof and normally supporting said cross bar out of contact with the ground, said wheels and said universal supporting means supporting said frame for movement over the ground with said forward cross bar in relatively close proximity to the ground, said forward cross bar moving upwardly and downwardly incident to variations in the vertical position of said supporting wheels at the front end of the frame and said universal supporting means with respect to the ground, whereby when the universal supporting means and the supporting wheels at the front end of the frame drop a predetermined amount with respect to the ground said forward cross bar will engage the ground to limit further downward movement of the forward end of said frame, a land planing device carried by said frame and comprising a rear wall having a lower horizontal cutting edge and side walls, the bottom of said device being open for the direct movement over the ground of earth cut by said cutting edge and pocketed within said device, and means connecting said frame to said universal supporting means and comprising a cable adapted to be pulled to elevate the forward end of said frame relative to said universal supporting means.

3. A land planing apparatus comprising a frame having forward and rear ends, relatively widely spaced supporting wheels for the rear end of said frame, a pair of relatively closely arranged wheels forwardly of said frame, connecting means between the forward end of said frame and said forward wheels comprising a universal connection whereby said forward wheels are laterally tiltable without communicating tilting movement to said frame, means pivotally connecting said connecting means to said frame, a boom fixed to said connecting means and extending rearwardly therefrom, and block and tackle means connecting said boom and the forward part of said frame for exerting a pull on said boom to swing it and vertically lift the pivotal connection between said connecting means and said frame to elevate the latter, and a cutting device fixed to said frame intermediate the ends thereof and comprising a rear wall having a lower cutting edge and side walls spaced apart a distance greater than the spacing of said rear supporting wheels.

4. A land planing apparatus comprising a frame having forward and rear ends, relatively widely spaced supporting wheels for the rear end of said frame, a pair of relatively closely arranged wheels forwardly of said frame, an axle connecting said last named wheels, a universal joint connected to said axle centrally thereof, a normally upwardly and rearwardly extending post connected at its lower end to said universal joint, means including a pivotal connection between said post and the forward end of said frame to support the latter relative to said post, a member fixed to said post and extending rearwardly therefrom, a pulley and cable device connecting said member and the forward part of the frame for exerting a force between said frame and said post for swinging the latter upwardly and forwardly to elevate said pivotal connection together with the forward end of said frame, and a cutting device fixed to said frame intermediate the ends thereof and comprising a rear wall having a lower cutting edge and side walls spaced apart a distance greater than the spacing of said rear supporting wheels.

5. A land planing apparatus comprising a frame having forward and rearward ends, spaced supporting wheels for the forward and rearward ends of said frame, said frame having horizontal side members spaced apart a distance greater than the spacing of said supporting wheels and connected at their forward ends by a crossbar, a cutting device adjustably secured to said frame intermediate the side members and comprising a rear wall having a lower horizontal cutting edge and spaced apart side walls, universal supporting means for the forward end of said frame connected to the supporting wheels at the forward end of the frame, said wheels and said universal supporting means supporting said frame for movement over "the ground with said cross bar in relatively close proximity to the ground, said cross bar moving upwardly and downwardly incident to variations in the vertical position of said supporting wheels at the forward end of the frame and said universal supporting means with respect to the ground, whereby when the universal supporting means andsaid supporting wheelsat the forward end of theframe drop a predetermined amount with respect to the ground said cross bar will engage the :ground to limit further downward movement of the forward end of said frame, and means connecting said frame to said universal supporting means and comprisinga cable adapted to be pulled to elevate the forward endof said frame relative to said universal supporting means.

6. A land planing apparatus comprising a frame having forward and rearward ends, relatively widely spaced supporting wheels at the rearward end of said frame, relatively narrowly spaced supporting wheels at the front end of said frame, said frame having a forward cross bar and spaced apart horizontal side members secured at their forward ends to said forward cross bar, a land planing device carried by said frame and comprising a rear wall having a lower horizontal cutting edge and side walls, the bottom of said device being open for the direct movement over the ground of earth cut by said cutting edge and pocketed within said device, universal supporting means for the forward end of said frame connected to said supporting wheels at the front end of'the frame centrally of the width thereof, said wheels and said universal supporting means supporting said frame for movement over the ground with said forward cross bar in relatively close proximity to the ground and normally supporting said cross bar out of contact with the ground, said forward cross bar moving upwardly and downwardly incident to variations in the vertical position of said supporting wheels at the front end of the frame and said universal supporting means with respect to the ground, whereby when the universal supporting means and said supporting wheels at the front end of the frame drop a predetermined amount with respect to the ground said forward cross bar will engage the ground to limit further downward movement of the forward end of said frame, and means connecting said frame to said universal supporting means and comprising a cable adapted to be pulled to elevate the forward end of said frame relative to said universal supporting means.

'7. A land planing apparatus comprising a horizontal frame having forward and rearward ends, vertically adjustable spaced apart wheels for supporting the rearward end of said frame in relation to the ground, universal supporting means for the forward end of said frame, an earth cutting device fixed to said frame and comprising a rear wall having a lower horizontal cutting edge and side walls spaced apart a distance greater than the spacing of said supporting wheels, and means connecting said frame to said universal supporting means including a post, a member fixed to said post and extending rearwardly therefrom, and a. cable connecting said member with the forward part of the frame and adapted to be pulled to elevate the forward end of said frame relative to 10 said universal supporting means and an adjus'table element for limiting the downward movement of'said frame relative to said universal supportingmeans when said cable is released.

8. A land planing apparatus comprising a frame having forward and rearwardends and including spaced apart horizontal side members, spaced supporting wheels for the rearward end of "said frame, adjustable means for securing said wheels to said frame whereby said wheels may be adjusted in vertical relation to said frame, universal supporting means for the forward end of said frame, a land planing device flxedto said frame and comprising a rear wall having'a lowerhorizontal cutting edge and side walls, said wheels and said universal supporting means supportingsaid frame for movement over the ground in relatively close proximity thereto, and means connecting said frame to said universal supporting means including a post, a member fixed to said post and extending rearwardly therefrom, and a cable connecting said member with the forward part of the frame and adapted to be pulled to elevate the forward end of said frame relative to said universal supporting means, and means for limiting the downward movement of said frame relative to said universal supporting means when said cable is released,

9. A land planing apparatus comprising a horizontal frame having forward and rear ends, spaced supporting wheels for the rear end of said frame, universal supporting means for the forward end of said frame, a cutting device fixed to said frame and comprising a rear Wall having a lower cutting edge and spaced side walls, and means connecting said frame to said universal supporting means and comprising a post, a pair of members fixed to said post and extending rearwardly therefrom, one of said members being pivotally connected to said frame, the other of said members being connected to the frame by a cable adapted to be pulled to elevate the forward end of said frame relative to said universal supporting means.

10. A land planing apparatus comprising a frame having forward and rear ends, relatively Widely spaced supporting wheels for the rear end of said frame, a pair of relatively closely arranged wheels forwardly of said frame, connecting means between the forward end of said frame and said forward wheels comprising a universal connection whereby said forward wheels are laterally tiltable without communicating tilting movement to said frame, means pivotally connecting said connecting means to said frame, a boom fixed to said connecting means and extending rearwardly therefrom, and block and tackle means between said boom and the forward part of said frame for exerting a pull on said boom to swing it and vertically lift the pivotal connection between said connecting means and said frame to elevate the latter, and a cutting device fixed to said frame intermediate the ends thereof and comprising a rear wall having a lower cutting edge and spaced side walls.

11. A land planing apparatus comprising a normally substantially horizontal frame having forward and rear ends, substantially spaced supporting wheels for the rearward end of said frame, a supporting structure for the forward end of said frame, said structure comprising an upwardly and rearwardly inclined post, relatively closely spaced forward supporting wheels beneath the forward end of said post, universal means connecting said forward wheels to the lower end of said post, and a downwardly and rearwardly extending member connected at its rear end to said frame near the bottom thereof and rigidly connected at its forward end to said post, a land planing device carried by said frame and comprising a rear wall having a lower horizontal cutting edge and side walls, the bottom. of said planing device being open, a rearwardly extending boom carried by said supporting structure and terminating within said frame beneath the top thereof, and block and tackle means connecting the rear end of said boom to the upper forward portion of said frame to exert a pull therebetween to rock said supporting structure at the point of contact of said forward wheels with the ground to elevate the forward end of said frame and lift said planing device out of engagement with the ground.

References Cited in the file of this patent Number UNITED STATES PATENTS 

